what causes the clutch to become super stiff

[trinisonic]

I recently changed the master and slave cylinders again, bled the entire system. the clutch pedal cannot go to the floor, it travels ¼ of the way and stays there, not returning to its normal position.
Thanks

[GeMc]

Sounds like a physical blockage in the clutch assembly (disk/pressure plate) or fork. Might have to drop the trans for this repair. I was initially going to say slave, but you swapped that already.

[MaxBell]

It could be that the system has air in it. The clutch takes a VERY long time to bleed, but it won't return if it's not done properly.

Can you push it to the floor, or does it feel like it's hitting something? If it does go to the floor and doesn't come back up, can you pull it back up?

The clutch is a hydralic system, so if it's being physically stopped, then it will most likely be something at the clutch pedal itself.

[SamE30e]

Is the slave installed properly, did the rod go in on an angle?

Or is a line kinked?

Chances are it's not inside the bell housing if worked before.